1. Field of the Invention
The present invention relates to a grinding apparatus for removing surface projections on a member to be ground by using an abrasive member.
2. Description of the Related Art
A liquid crystal display (hereinafter referred to as "LCD") includes a polarizing film which is provided, for example, on a surface side of a liquid crystal. The polarizing film brightens or darknens in accordance with whether or not the light having transmitted through the liquid crystal transmits through the polarizing film, and thus an image is displayed. Such LCD includes a color filter which contains minute filter-components, of colors such as green, blue and red, arranged in a mosaic state. The color filter is arranged between the liquid crystal and the polarizing film. The light transmitting through the polarizing film is subjected to filtration so as to display a color image.
When projections or foreign matters adhere to a surface of a color filter and a gap is produced between a polarizing film and the color filter due to the projections or foreign matters, it is impossible for the polarizing film to shield unnecessary light. It therefore becomes impossible to clearly display an image, as well as to display a vivid color image. For this reason, the color filter used for color LCD should be prevented from minute projections or foreign matters on the surface.
The allowable range for surface projections on a color filter used for color LCD is generally considered to be not more than about 4 .mu.m. It is necessary to remove projections or foreign matters larger than the above from the surface of the color filter. In this removal, since the surface of the color filter is soft, careful attention should be paid so as not to apply unnecessary external force, and thus the operation should be conducted precisely and certainly.
An apparatus for automatically grinding a surface of a color filter as described above includes one in which the surface of the color filter is examined by using a laser length measuring machine or the like, the position and the height of projections are calculated, and then the projections are ground on the basis of a calculation result by using an abrasive member to be not more than a predetermined size.
However, such an automated grinding apparatus is exquisite, has a complicated structure, and is extremely expensive. For this reason, the operation for grinding the surface of the color filter is conducted in a conventional manner. Namely, a method is generally adopted in which an operator visually examines whether or not large projections or foreign matters are present on the surface of the color filter, and when large projections or foreign matters are found, they are ground and removed manually little by little by using an abrasive member such as an abrasive tape with abrasive particles. Therefore, careful attention is required.